docs: def _random_color(h_range=(0., 1.),
                    s_range=(.5, 1.),
                    v_range=(.5, 1.),
                    ):
      """Generate a random RGB color."""
      h, s, v = uniform(*h_range), uniform(*s_range), uniform(*v_range)
      r, g, b = hsv_to_rgb(np.array([[[h, s, v]]])).flat
      return r, g, b